Published on 12, July, 2020
II had mine done a few months ago and it was really interesting, I'm 88% southern English with a smattering of European and 8% Iberian. To have such a high percentage in one area is quite unusual, if true, I dont' know where the Iberian link comes in, I can't see anything in the ancestors I've already traced that would suggest Iberian ancestry. 8% would mean that it's a fairly recent addition grand parents or great grandparents and they all came from southern England, more specifically Kent, Sussex and Berkshire.
My Mum had hers done and she's real mix of British, Scandinavian, Welsh and European but no Iberian, so if it's true that I have some Iberian ancestry then it dosen't come from her, we know her Welsh connection, thats her great grandad, but she's only got 4% Welsh, so you can see my quandary with 8% Iberian?
I might get it done again, with a different company and get my haplotypes done too, I think it would be really fascinating to know my deep ancestry, when my people came to Europe and by what route, are they fairly recent, or have they been here since the end of the Ice Age?
In answer to your Iberian query, there are a number of ways that you could have inherited 8% Iberian DNA, One is a single recent ancestor, or, alternatively, through multiple more distant ancestors in separate ancestral lines. A single gt.gt. grandparent could give you around 8% DNA, but so could 2 gt.gt.gt. grandparents. The problem is that although you get very close to 50% DNA from each parent, because of random sorting on chromosomal chiasma (crossing over between paired chromosomes during the production of sperm and ova) this arithmetical progression soon breaks down the further back you go in generations. In practice, you could easily get twice as much DNA from one gt.gt. grandparent as you get from another.
In your cells you have paired chromosomes (except XY in males), one chromosome from each parent, But in sex cells, spermatozoa and ova, there is only a single copy of each pair, but this copy is a composite between the paternal and maternal chromosomes you inherited, due to random sections of DNA of these chromosomes switching between them - chiasma - during meiosis leading to sperm and egg production.
Am I correct that your profession was in genetics Martin?
Yes, molecular biology, but of pathogens, not humans.
Good to have your input here then.